Power switches for connecting a load to a power source are commonplace. In the field of addressable lighting, for example, addressable power switches may be used to selectively connect lamps to the mains.
A known addressable power switch is connected to low power control lines and responds to switching commands containing its unique address by connecting or disconnecting one or more lamps, or their ballasts, to line power. The low power control lines may, in some embodiments, conform to the digital addressable lighting interface (DALI) standard described in IEC 60929. In others, they may conform to the digital signal interface (DSI) standard. In yet others, the control lines may be based on a proprietary interface. In any event, the known addressable power switch includes a relay for connecting the lamps to line power. In many cases the relay is a fail-open relay and the lamps are connected to line power only when the relay is energized. A control unit within the addressable power switch monitors the low power control lines and detects switching commands addressed to it. The control unit outputs a control signal to connect the relay to the low power control lines to energize the relay.
It would be advantageous to provide an addressable power switch with improved power efficiency.